[RFC 29/41] hw/core/slot: Statistics topology information in CPU slot

[Zhao Liu <zhao1.liu@xxxxxxxxxxxxxxx>]

From: Zhao Liu <zhao1.liu@xxxxxxxxx>

The CPU slot, as the root of the topology tree, is responsible for
global topology information collection and updates.

When a new topology device is added to/deleted from the topology tree,
update the corresponding information in the slot.

Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
 hw/core/cpu-slot.c         | 41 +++++++++++++++++++++++++++++++++++-
 include/hw/core/cpu-slot.h | 43 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/hw/core/cpu-slot.c b/hw/core/cpu-slot.c
index a6b7d98dea18..e8e6f4d25532 100644
--- a/hw/core/cpu-slot.c
+++ b/hw/core/cpu-slot.c
@@ -22,14 +22,44 @@
 
 #include "hw/core/cpu-slot.h"
 
+static inline
+CPUTopoStatEntry *get_topo_stat_entry(CPUTopoStat *stat,
+                                      CPUTopoLevel level)
+{
+    assert(level != CPU_TOPO_UNKNOWN);
+
+    return &stat->entries[TOPO_STAT_ENTRY_IDX(level)];
+}
+
 static void cpu_slot_add_topo_info(CPUTopoState *root, CPUTopoState *child)
 {
     CPUSlot *slot = CPU_SLOT(root);
     CPUTopoLevel level = CPU_TOPO_LEVEL(child);
+    CPUTopoStatEntry *entry;
 
     if (level == CPU_TOPO_CORE) {
-        QTAILQ_INSERT_TAIL(&slot->cores, CPU_CORE(child), node);
+        CPUCore *core = CPU_CORE(child);
+        CPUTopoStatEntry *thread_entry;
+
+        QTAILQ_INSERT_TAIL(&slot->cores, core, node);
+
+        /* Max CPUs per core is pre-configured by "nr-threads". */
+        slot->stat.max_cpus += core->nr_threads;
+        slot->stat.pre_plugged_cpus += core->plugged_threads;
+
+        thread_entry = get_topo_stat_entry(&slot->stat, CPU_TOPO_THREAD);
+        if (child->max_children > thread_entry->max_units) {
+            thread_entry->max_units = child->max_children;
+        }
     }
+
+    entry = get_topo_stat_entry(&slot->stat, level);
+    entry->total_units++;
+    if (child->parent->num_children > entry->max_units) {
+        entry->max_units = child->parent->num_children;
+    }
+
+    set_bit(level, slot->stat.curr_levels);
     return;
 }
 
@@ -37,10 +67,18 @@ static void cpu_slot_del_topo_info(CPUTopoState *root, 
CPUTopoState *child)
 {
     CPUSlot *slot = CPU_SLOT(root);
     CPUTopoLevel level = CPU_TOPO_LEVEL(child);
+    CPUTopoStatEntry *entry;
+
+    assert(level != CPU_TOPO_UNKNOWN);
 
     if (level == CPU_TOPO_CORE) {
         QTAILQ_REMOVE(&slot->cores, CPU_CORE(child), node);
     }
+
+    entry = get_topo_stat_entry(&slot->stat, level);
+    entry->total_units--;
+
+    /* No need to update entries[*].max_units and curr_levels. */
     return;
 }
 
@@ -73,6 +111,7 @@ static void cpu_slot_instance_init(Object *obj)
     CPUSlot *slot = CPU_SLOT(obj);
 
     QTAILQ_INIT(&slot->cores);
+    set_bit(CPU_TOPO_ROOT, slot->stat.curr_levels);
 }
 
 static const TypeInfo cpu_slot_type_info = {
diff --git a/include/hw/core/cpu-slot.h b/include/hw/core/cpu-slot.h
index d2a1160562be..fa2bd4af247d 100644
--- a/include/hw/core/cpu-slot.h
+++ b/include/hw/core/cpu-slot.h
@@ -25,6 +25,47 @@
 #include "hw/cpu/core.h"
 #include "hw/qdev-core.h"
 
+/**
+ * @USER_AVAIL_LEVEL_NUM: the number of total topology levels in topology
+ *                        bitmap, which includes CPU_TOPO_UNKNOWN.
+ */
+#define USER_AVAIL_LEVEL_NUM (CPU_TOPO_ROOT + 1)
+
+/**
+ * @VALID_LEVEL_NUM: the number of valid topology levels, which excludes
+ *                   CPU_TOPO_UNKNOWN and CPU_TOPO_ROOT.
+ */
+#define VALID_LEVEL_NUM (CPU_TOPO_ROOT - 1)
+
+#define TOPO_STAT_ENTRY_IDX(level) ((level) - 1)
+
+/**
+ * CPUTopoStatEntry:
+ * @total: Total number of topological units at the same level that are
+ *         currently inserted in CPU slot
+ * @max: Maximum number of topological units at the same level under the
+ *       parent topolofical container
+ */
+typedef struct CPUTopoStatEntry {
+    unsigned int total_units;
+    unsigned int max_units;
+} CPUTopoStatEntry;
+
+/**
+ * CPUTopoStat:
+ * @max_cpus: Maximum number of CPUs in CPU slot.
+ * @pre_plugged_cpus: Number of pre-plugged CPUs in CPU slot.
+ * @entries: Detail count information for valid topology levels under
+ *           CPU slot
+ * @curr_levels: Current CPU topology levels inserted in CPU slot
+ */
+typedef struct CPUTopoStat {
+    unsigned int max_cpus;
+    unsigned int pre_plugged_cpus;
+    CPUTopoStatEntry entries[VALID_LEVEL_NUM];
+    DECLARE_BITMAP(curr_levels, USER_AVAIL_LEVEL_NUM);
+} CPUTopoStat;
+
 #define TYPE_CPU_SLOT "cpu-slot"
 
 OBJECT_DECLARE_SIMPLE_TYPE(CPUSlot, CPU_SLOT)
@@ -35,6 +76,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(CPUSlot, CPU_SLOT)
  *     where the cpu-slot is the root. cpu-slot can maintain similar
  *     queues for other topology levels to facilitate traversal
  *     when necessary.
+ * @stat: Statistical topology information for topology tree.
  */
 struct CPUSlot {
     /*< private >*/
@@ -42,6 +84,7 @@ struct CPUSlot {
 
     /*< public >*/
     QTAILQ_HEAD(, CPUCore) cores;
+    CPUTopoStat stat;
 };
 
 #endif /* CPU_SLOT_H */
-- 
2.34.1